| From: | Jeffrey Melloy <jmelloy(at)visualdistortion(dot)org> |
|---|---|
| To: | "Williams, Travis L, NEO" <tlw(at)att(dot)com> |
| Cc: | "Thomas A(dot) Lowery" <tlowery(at)stlowery(dot)net>, <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: Join question |
| Date: | 2003-08-29 05:44:12 |
| Message-ID: | D1319B84-D9E3-11D7-8AF9-000393C78AC0@visualdistortion.org |
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| Lists: | pgsql-general |
On Friday, August 29, 2003, at 12:36 AM, Williams, Travis L, NEO wrote:
> Performace wise would I be better off just doing 2 query's.. i.e.
> select
> a,b from table1.. then in perl I can check if b is not null and if is
> isn't then I do a second query?
>
> Travis
>
I would say it depends on the table distribution (% of b that are null,
etc). At that point, you're just going to have to experiment, I think,
and see what works best for you. My gut says that even including a
subselect, it will be faster than checking in perl and issuing another
query. But I have no idea, and the proper solution might change
drastically based on your data.
Jeff
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